Lithographic materials containing metal complexes

ABSTRACT

A photographic element is disclosed which comprises a support having coated thereon at least one layer comprising a photographic silver halide emulsion and in said layer or in a second layer adjacent thereto from about 0.2 to about 5.0 grams per mole of silver of at least one hexacoordinated trivalent cationic complex comprising a trivalent metal ion selected from the group consisting of cobalt (III) and chromium (III) in combination with at least one ligand selected from the group consisting of ammonia, ethylene diamine, trimethylene diamine, diethanolamine and dipropanolamine; said silver halide emulsion comprising silver halide grains in which the halide consists of at least about 50 mole percent chloride, up to about 10 mole percent iodide and any remaining halide being bromide.

United States Patent Beavers LITHOGRAPIIIC MATERIALS CONTAINING METAL COMPLEXES [75} Inventor: Dorothy Johnson Beavers,

Rochester, NY.

[73] Assignee: Eastman Kodak Company,

Rochester, NY.

[22] Filed: Sept. 18, 1973 [21] Appl. No.: 398,515

Related U.S. Application Data [63] Continuation-impart of Ser. No, 312,159, Dec. 4,

1972, abandoned.

[52] U.S. Cl 96/76 R; 96/87 R; 96/66.3; 96/107; 96/108; 96/95 [51] Int. Cl. G03c 1/48; G03c 1/06; G030 1/28 [58] Field of Search 96/107, 108, 95, 66.3, 96/87 R, 76 R [56] References Cited UNITED STATES PATENTS 3,671,258 6/1972 Taber 96/107 3,748,138 7/1973 Bissonette 96/66.3

[ June 24, 1975 FOREIGN PATENTS OR APPLICATIONS 1,248,530 10/1971 United Kingdom 96/107 Primary Examiner-Won H. Louie, Jr. Attorney, Agent, or FirmC. 0. Thomas [57] ABSTRACT A photographic element is disclosed which comprises a support having coated thereon at least one layer comprising a photographic silver halide emulsion and in said layer or in a second layer adjacent thereto from about 0.2 to about 5.0 grams per mole of silver of at least one hexacoordinated trivalent cationic complex comprising a trivalent metal ion selected from the group consisting of cobalt (111) and chromium (111) in combination with at least one ligand selected from the group consisting of ammonia, ethylene diamine, trimethylene diamine, diethanolamine and dipropanolamine; said silver halide emulsion comprising silver halide grains in which the halide consists of at least about 50 mole percent chloride, up to about 10 mole percent iodide and any remaining halide being bromide.

15 Claims, No Drawings LITHOGRAPI-IIC MATERIALS CONTAINING METAL COMPLEXES CROSS-REFERENCE TO RELATED APPLICATION This is a continuation-in-part of U.S. Ser. No. 312,159 filed Dec. 4, I972 now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to photographic materials, their preparation and use. In one aspect, this invention relates to photographic elements containing hexacoordinated trivalent cationic complexes. In another aspect, this invention relates to photographic elements containing such complexes and further containing an azaindene.

2. Description of the Prior Art Cadmium salts have long been employed in the photographic field for a variety of purposes. For example, it is stated in Glafkides, Photographic Chemistry", Vol. 1, I958, page 151, that cadmium chloride can be used to increase the contrast in the silver halide emulsion. US. Pat. No. 3,488,709 issued Jan. 6, 1970 to Sidebotham teaches that cadmium bromide stabilizes silver halide emulsions precipitated in the presence of rhodium salts in that it reduces the loss of contrast and speed change upon storage annd also that cadmium bromide acts to increase the contrast in a synergistic manner.

Although the concentrations of cadmium bromide taught by Sidebotham are relatively small, i.e., 20 to about 60 grams per mole of silver halide, the elimination or reduction of such cadmium salts appears to be ecologically advantageous since, during film processing, such cadmium salts are eventually washed out and may find their way into the environment. It is known that cadmium interferes with zinc and copper metabolism and is harmful to living organisms. Cadmium can be found not only in the atmosphere but also in marine life, such as in fish found in waters wherein cadmium is present in high levels.

In view of the now recognized toxicity of cadmium and other trace metals, concern for the public health and the maintenance of a more normal ecological balance has led to a search for new means of achieving good properties in photographic compositions by utilizing relatively non-toxic materials or, where necessary, substantially reduced amounts of toxic materials. One means of achieving this is described in Product Licensing Index, Vol. 100, August, 1972, publication 10014, wherein at least part of the cadmium salt is replaced by a water soluble manganous salt. Despite the advantages of this development, however, a need still exists for improved photographic compositions which do not contain cadmium salts but which exhibit the increased photographic speed and the development acceleration obtainable with cadmium salts.

SUMMARY OF THE INVENTION The present invention comprises improved photographic elements which contain a metal complex and, optionally, an azaindene in the silver halide layer or in a second layer adjacent thereto in place of a cadmium salt.

More particularly, the present invention comprises a photographic element comprising a support having coated thereon a least one layer comprising a photographic silver halide emulsion in the said layer or in a second layer adjacent thereto from about 0.2 to about 5.0 grams per mole of silver of at least I hexacoordinated trivalent cationic complex comprising a trivalent metal ion selected from the group consisting of cobalt (III) and chromium (III) in combination with at least one ligand selected from the group consisting of ammonia, ethylene diamine, trimethylene diamine, diethanol amine and dipropanol amine; said silver halide emulsion comprising silver halide grains in which the halide consists of at least about 50 mole percent chloride, up to about 10 mole percent iodide and any remaining halide being bromide. In another aspect, the present invention comprises above-described photographic element further comprising at least one azaindene.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The cationic complexes of this invention comprise an ion surrounded by certain other molecules which are referred to as ligands. The ion in the center of these complexes is a Lewis acid; the ligands are Lewis bases. Werner complexes are well known examples of such complexes.

The metal complexes of this invention have coordination numbers of 6 and are known as octahedral complexes. As stated above, the metal ions which can be employed to prepare the complexes of this invention are cobalt (III) or chromium (III). Complexes based upon cobalt (III) are preferred.

The ligands employed in the practice of this invention comprise ammonia, ethylene diamine, trimethylene diamine, diethanol amine and dipropanol amine. Accordingly, as exemplary of those hexacoordinated trivalent cationic complexes which can be employed in the practice of this invention can be listed hexammine cobalt (III), tris(ethylenediamine) cobalt (Ill), bis(diethanol amine)cobalt (III), bis(dipropanol) amine cobalt (III), hexammine chromium ([II), tris(ethylenediamine) chromium (III), bis(diethanolamine) chromium (III), bis(dipropanolamine) chromium (III), tris(trimethylenediamine) cobalt (III), tris(trimethylenediamine) chromium (III), ethylenediaminebis(trimethylenediamine) cobalt (III), ethylenediaminebis(- trimethylenediamine) chromium (III), bis(ethylenediamine) trimethylenediamine cobalt (III), bis (ethylened iamine)trimethylenediamine chromium (III) and the like.

There will, of course, be anions associated with the foregoing complex actions. Any anion which does not exert undesirable effects upon the finished photographic element may be employed. Among those anions which will be found useful may be listed chloride, bromide, sulfite, sulfate, perchlorate, nitrite, acetate, and the like.

These metal complexes are located in the photographic elements of this invention either in the layer comprising the photographic silver halide emulsion or in a layer immediately adjacent thereto. They are present in a concentration of from about 0.2 to about 5.0 grams per mole of silver. A preferred range is from about 0.3 to about 3.0 grams of metal complex per mole of silver and the most preferred range is from about 0.5 to about 1.0 gram of metal complex per mole of silver.

It is preferred that the complexes employed in the practice of this invention have a reduction potential (E,) in the range of from about 0.2 to about 0.8 volt when measured in a carbonate buffer solution at pH 10.

The photographic silver halide emulsions employed in the practice of this invention are lithographic silver halide emulsions in which the halide generally comprises at least about 50 mole percent chloride, up to about mole percent iodide and any remaining halide being bromide. These high contrast emulsions preferably contain at least 60 mole percent chloride, less than 40 mole percent bromide and less than 5 mole percent iodide. Suitable silver halides include, for example, silver chloride, silver chlorobromide, silver chlorobromoiodide and the like.

It is preferred that the photographic elements of this invention further comprise at least one azaindene, located either in the photographic silver halide emulsion layer or in a layer immediately adjacent thereto. The azaindene will generally be present in a concentration of from about 0.2 to about 5.0 grams per mole of silver, preferably from about 0.3 to about 3.0 grams per mole of silver and, most preferably, from about 0.5 to about 1.0 gram per mole of silver, Among those azaindenes which may be employed in the practice of this invention can be listed, for example, 4-hydroxy-6-alkyl- 1,3,3a, 7-tetrazaindenes, such as, 4hydroxy-6-methyl- 1,3,3a, 7-tetrazaindene, 5-carboxy-4-hydroxy-1,3,3a, 7-tetrazaindene, 6-methyl-1,3,3a, 7-tetrazaindene-4- thiol, 5,7-dimethyl-4,6-dioxo-4,5,6,7tetrahydrol,2,3,5,7-pentazaindene, 6-phenyl-l ,3,3a, 7-tetrazaindene-4-thiol, 5-bromo-6-methyl-I ,3, 3a, 7-tetrazaindene-4-thiol, 2,6-dimethyl-l,3,3a, 7-tetrazaindene-4- thiol, 6-methyl-2-rnethylthio-1,3,3a, 7-tetrazaindene-4- thiol, 5-ethyl-6-methyl-1,3,3a, 7-tetrazaindene-4-thiol, 5-iso-butyl-6-methyll ,3,3a, 7-tetrazaindene4-thiol, 5-phenyl-1,2,3a, 4-tetrazaindene-7-thiol, 6-ethyl-5- methyl-1,2,3a, 4-tetrazaindene-7-thiol, S-methyl- 1,2,3a, 4-tetrazaindene-7-thiol, l,2,-bis(4-hydroxy-6- methyl-1,3 ,3a, 7-tetrazainden-2-yl )-l ,2- dihydroxyethane, ,6-bis(4-hydroxy-6-methyl-l ,3,3 a, 7-tetrazainden-2-yl )-2,5-dioxahexane, l,2-bis( 4- hydroxy-6-methyl-1,3,3a, 7-tetrazainden-2-yl)ethane, l,4-bis(4-hydroxy-6-methyl-1,3,3a, 7-tetrazainden-2- yl )butane, 1,2,3,4-tetrakis(4-hydroxy6-methyl-l ,3,3a, 7-tetrazainden-2 -yl)butane, 5-amino-7-l'iydroxy-2- phenyl-l,2,3,4,6-pentazaindene, 7-amino-5-mercapto- 2-p-sulfophenyll ,2,3,4,6-pentazaindene, 5-amino-2-pcarboxyphenyl-7-hydroxy-1,2,3,4,6-pentazaindene, 5, 7-diamino-2-phenyll ,2,3,4,6-pentazaindene, 7-amino- 5-dimethylamino-2-phenyl-l ,2,3,4,6-pentazaindene, 5-dimethylamino-7-hydroxy-Z-phenyl-l ,2,3,4,6- pentazaindene, 2-p-aminophenyl5-amino-7-hydroxy- 1,2,3 ,4,6-pentazaindene, 5-amino-7-hydroxy-2-pmethoxyphenyl-l ,2,3,4,6-pentazaindene, 5-amino-2-pchlorophenyl-7-hydroxy-l ,2,3,4,6-pentazaindene, 5- amino-2-hydro-7-hydroxy-1,2,3,4, 6-pentazaindene, 5,7-dihydroxyl ,2,3,4,6-pentazaindene, 7-hydroxy-5- methyl-l ,2,3,4,6-pentazaindene, 7-hydroxyl ,2,3 ,4,6- pentazaindene, 7-hydroxy-5-mercapto-l ,2,3 ,4,6- pentazaindene, 7-amino-5-carboxy-methylmercapto- 1,2,3 ,4,6-pentazaindene, 7-mercapto-1,2,3, 4,6-

pentazaindene, 5 ,7-dimercapto-l ,2,3 ,4,6- pentazaindene, 5-ethylmercapto-7-hydroxy-l ,2,3 ,4,6- pentazaindene, 5-hydroxy-1,2,3, 4,6'pentazaindene,

5-hydroxy7-mercapto-1,2,3 ,4,6-pentazaindene, 5- hydroxy-7-methyl-l ,2,3,4,6-pentazaindene,

2,4-dihydroxy6-methyl-1,3a, 7 triazaindene, 4- hydroxy-5-chloro-l,3,3a, 7-tetrazaindene, 4-hydroxy- 5-iodo-l,3,3a, 7-tetrazaindene, 2-methyl-4-hydroxy-6- methyl-3,3a, 7-tria2aindene and the like. These azaindenes as well as others which can be employed in the practice of this invention are known in the art and have been described, for example, in Heimbach et al. US, Pat. Nos. 2,444,605 issued July 6, 1948; Allen et al., 2,713,541 issued July 19, 1955; Carroll et al. 2,716,062 issued Aug. 23, 1955; Allen et al. 2,735,769 issued Feb. 21, 1956; Allen et al. 2,743,181 issued Apr. 24, I956; Tinker et al, 2,835,581 issued May 20, 1958; Reynolds 2,756,147 issued July 24, 1956; Tinker 2,852,375 issued Sept. 16, 1958; Carroll et al. 2,743,180 issued Apr. 24, 1956; Knott 2,933,388 issued Apr. 19, 1960; Carroll et al. 2,944,900 issued July 12, 1960; 3,432,304 Saleck et al. issued Mar. 11, 1969; lshikawa et al. 3,526,507 issued Sept. 1, 1970; Baldock et 211. 3,573,056 issued Mar. 30, 1971; British Specification No. 1,270,734 to Konishiroku Photo Industry Co., Limited published Apr. 12, 1972 and Zeitschrift Fuer Wiss. Phot. 47, 2-28 (1952) and Piper 2,886,437 issued May 12, 1959.

Although not critical to the present invention, it will be very convenient, and thus preferred, if a continuous method is employed for processing the exposed high contrast photographic elements. In such a method, the element is processed in one continuous motion by transporting it into and out of at least one processing solution in the manner shown, for example, by U.S. Pat. Nos. 3,025,779 of Russell and Kunz issued Mar. 20, 1962; 3,078,024 of Sardeson issued Feb. 19, 1963; 3,122,086 of Fitch issued Feb. 25, 1964; 3,149,551 of Cramer issued Feb. 22, 1964; 3,156,173 of Meyer issued Nov. 10, 1964; and 3,224,356 of Fleisher and Hixon issued Feb. 21, 1965.

It is important, however, that the photographic elements of this invention upon exposure be developed in developers containing one or more amines and/or amine derivatives. A particularly desirable developer composition is described in Masseth U.S. Pat. No. 3,573,914 which comprises a developing agent, a carbonyl bisulfite-amine condensation product, and at least about 0.075 mole of free amine per liter of developer composition.

The developing agents which can be employed in these developer compositions can be any of those suitable for the intended purpose. Suitable silver halide developing agents, for example, include the dihydroxybenzenes such as hydroquinone, chlorohydroquinone, bromohydroquinone, isopropylhydroquinone, toluhydroquinone, methylhydroquinone, 2,3- dichlorohydroquinone, 2,5-dimethylhydroquinone,

2,3-dibromohydroquinone, 1,4-dihydroxy -2- acetophenone-2,5-dimethylhydroquinone, 2,5-di-pphenthylhydroquinone, 2 ,5- dibenzoylaminohydroquinone, 2 ,5-

diacetaminohydroquinone, etc. Esters of such compounds, e.g., formates and acetates, can also be employed. These developing agents can be used alone or in any combination and can be employed in any con centration which is effective for development. A suitable concentration for the developing agent is from about 0.05 to about 0.50 mole per liter of developer composition and is preferably from about 0.10 to about 0.03 mole per liter of developer composition.

The carbonyl bisulfite-amine condensation products which can be used in this developer composition are r ferably formaldehyde bisulfite-amine condensation products such as sodium-Z-hydroxyethylaminomethane sulfonate, sodium-2-hydroxy-propylaminomethane sulfonate, sodium-l l -dimethyl-2-hydroxylaminomethane sulfonate, sodium-l.l bis(hydroxymethyl )ethylaminomethane sulfonate, sodiumtris( hyd roxymethyl )methylaminomethane sulfonate, sodium-3-hydroxypropylaminomethane sulfonate,

sodium-bis(2 hydroxyethyl)aminomethane sulfonate, sodium-N,N-bis( 2-[ l-hydroxy1propyl)aminomethane sulfonate, sodium-N-isopropyl-N-(Z-hydroxyethyl )aminomethane sulfonate, sodium-N-ethyl-N-( 2- hydroxyethyl)aminomethane sulfonate, and sodium-N- methyl-N-(Z-hydroxyethyl)aminomethane sulfonate. The carbonyl bisulfiteamine condensation products can be used alone or in any combination and can be employed in any concentration which is effective to provide a low level of sulfite ion for the developer composition. A suitable concentration for the carbonyl bisulfiteamine condensation product is from about 0.1 to about l.0 mole per liter of liquid developer composition and is preferably from about 0.25 to about 0.50 mole per liter of liquid developer composition.

The carbonyl bisulfite-amine condensation product can be added to the developer composition as a separate compound or formed in situ. Methods for preparing these compounds are disclosed, for example, in U.S. Pat. No. 2,388,816 of Bean issued Nov. 13, I945.

The free or uncombined amine compounds which can be employed in these developer compositions include primary and secondary amines such as 2- aminoethanol, I-amino-2-propanol, 2-amino-2-methyll-propanol, 2-amino-2-methyl-l,3-propanediol, 2- amino-2(hydroxymethyl)-1,3-propanediol, 3-aminolpropanol, 2-2'-imin0diethanol, di-iso-propanolamine, 2-isopropylamino-ethanol, 2-ethylaminoethanol, 2- methylaminoethanol, etc. These amines can be used alone or in any combination and should be employed in a concentration of at least about 0.075 mole per liter of developer composition. A suitable range of concentrations from the amine compound is from about 0.075 to about 3.0 moles per liter of developer composition and is preferably from about 0.20 to about 0.90 mole per liter of developer composition. The free amine present in the developer composition can be the same amine used to prepare the carbonyl bisulfite-amine condensation product or it can be a different amine.

The silver halide emulsion layer of the high contrast photographic elements of this invention can contain any of the hydrophilic water-permeable binding materials suitable for this purpose. Suitable materials include gelatin, colloidal albumin, polyvinyl compounds, cellulose derivatives, acrylamide polymers, etc. Mixtures of these binding agents can also be used. The binding agents for the emulsion layer of the high contrast photographic element can also contain dispersed polymerized vinyl compounds. Typical synthetic polymers include those described in Nottorf U.S. Pat. Nos. 3,142,568 issued July 28, I964; White 3,193,386 issued July 6, 1965; Houck et al. 3,062,674 issued Nov. 6, 1962; Houck et al. 3,220,844 issued Nov. 30, I965; Ream et al. 3,287,289 issued Nov. 22, 1966; and Dykstra 3,4] l,9ll issued Nov. 19, I968. Other vehicle materials include those water insoluble polymers of alkyl acrylates and methacrylates, acrylic acid, sulfoalkyl acrylates or methacrylates, those which have crosslinking sites which facilitate hardening or curing as described in Smith U.S. Pat. No. 3,488,708 issued Jan. 6, I970 and those having recurring sulfobetaine units as described in Dykstra, Canadian Pat. No. 774,054. These compounds can also be incorporated into a separate layer of the photographic element. The vinyl polymers are generally employed in concentrations in the range of about 20 to about percent, most often concentrations at least 50 percent, by weight, based on the weight of the binding agent. Silver halide emulsions wherein the binding agent contains dispersed polymerized vinyl compound provide particularly good results in eliminating drag streaks and dot distortions.

The silver halide emulsion of the high contrast photographic elements of this invention can be coated on a wide variety of supports. Hydrophilic colloid layers can be coated on one or both sides of the support if desired. Typical supports are cellulose nitrate film, cellulose ester film, polyvinylacetal film, polystyrene film, poly- (ethylene terephthalate) film, polycarbonate film and related films or resinous materials as well as glass, paper, metal and the like. Typically, a flexible support is employed, especially a paper support, which can be partially acetylated or coated with baryta and/or an alpha-olefin polymer, particularly a polymer of an alphaolefin containing 2 to ID carbon atoms such as polyethylene, polypropylene, ethylene butene copolymers and the like.

The silver halide emulsions of the high contrast photographic elements of this invention can be sensitized using any of the well known techniques in emulsion making, for example, by digesting with naturally active gelatin or various sulfur, selenium, tellurium compounds and/or gold compounds. The emulsions can be sensitized with salts of noble metals of Group VIII of the Periodic Table which have ann atomic weight greater than I00. The emulsions can also contain addenda which increase speed and/or contrast such as quaternary ammonium salts, thioether sensitizers or combinations thereof.

The silver halide emulsions of the high contrast photographic elements of this invention can conveniently be ortho-sensitized or pan-sensitized with spectral sensitizing dyes. Sensitizing dyes useful in sensitizing these silver halide emulsions are described, for example, in Brooker et al. U.S. Pat. Nos. 2,526,632 issued Oct. 24, 1950; Sprague 2,503,776 issued Apr. I l, 1950; Brooker et al. 2,493,748 issued Jan. I0, 1950; and Taber et al. 3,384,486 issued May 21, I968. Spectral sensitizers which can be used include the cyanines, merocyanines, complex (trior tetranuclear) cyanines, holopolar cyanines, styryls, hemicyanines (e.g., enamine cyanines), oxonols and hemioxonols.

The silver halide emulsions of the high contrast photographic elements of this invention can also contain conventional addenda such as gelation plasticizers, coating aids, antifoggants and hardeners as described in Product Licensing Index, V0. 92, December, I971, publication 9232, pages 107-l l0.

The silver halide photographic elements of this invention are used for making lithographic printing plates such as by the colloid transfer of undeveloped and unhardened areas of an exposed and developed emulsion to a suitable support as described in Clark et al. U.S. Pat. No. 2,763,553 issued Sept. 18, 1956; to provide a relief image as described in Woodward 3,402,045 issued Sept. l7, I968 or Spencer 3,053,658 issued Sept. 1 l, 1962; to prepare a relief printing plate as described in Baxter et al. U.S. Pat. No. 3,271,150 issued Sept. 6, 1966; to prepare a silver salt diffusion transfer plate as 8 is then processed in a Kodalith Roller Transport Film Processor of the type shown in U.S. Pat. No. 3,025,779 to Russell and Kunz at 2.3 feet per minute. The processor contains the following developer composition:

described in l-lepher et al. British Pat. No. 934,691 is- Sdium bis (zmwimwemmaminm 82D 8 sued Aug. 21, 1963 and Agfa Br1t|sh Pat. No. 883,846 methane sulfonate issued Dec. 6, 1961 to provide an element which does gzi 'z'z is 3:? 5: not require washing or etching as described in Yeckel Hydroquinone 22.5 g et al. U.S. Pat. No. 3,l46,l04, reissue 25,885. ffi m figfigg 33 8 Alkylene oxides can also be utilized in the practice of 10 l w make 3 this invention. Typical useful compounds include poly- P ethylene glycol, polyethylene glycol oleyl ether, polyethylene glycol cetyl ether, polyethylene oxide deriva- The results are Show" Table tives, block copolymers such as those comprising EXAMPLE 2 blocks of polyoxypropylene, polyoxyethylene and the like, water-soluble organosilicone polyalkylenoxide E p e I IS repeated except that 1.0 gram of hexpolymers and the like. The alkylene oxide polymer can ammine cobalt (III) chloride per mole of silver is added be used in any concentration effective for the intended to the emulsion prior to coating. The results are shown purpose. When the alkylene oxide polymer is present i T bl in the photographic element, good results are obtained when the concentration is less than about 2 grams per EXAMPLE 3 mole of stlver 1n the stlver hal1de emulsron. preferred Example 2 is repeated except m-s(ethylenediamine) range for the polymer this cobalt (III) chloride is substituted on an equal weight ment ts from about 10 to about 800 mg. per mole of Sllbasts for the hexammme cobalt (III) chlonde employed ver In the silver halide emulslon. When the alkylene h Th I h T bl I oxide polymer is present in the photographic develt c ts are 5 Own m a e oper, good results are generally obtained when the EXAMPLE 4 polymer is employed in a concentration of from about OJ to about 10 grams per liter of developer composi Example 2 1s repeated except hexammine cobalt (Ill) lion, acetate is substituted on an equal weight basis for the The following examples are included for a further unhexammine cobalt (III) chloride employed therein. The derstanding of the invention. results are shown in Table I.

TABLE I Incubation Fresh 7 days at l20F %RH Curve Feature Rel. Dot Compre- Rel. Example g/mole Ag Speed Gamma Fog Quality ssion' Speed Gamma Fog 1 None 100 12.15 .04 6 0.60 159 7.0 .11 2 A 1.0 224 9.70 .04 7 0.15 148 1 1.87 .04 3 B 1.0 389 11.72 .04 7 0.30 159 12.17 .04 4 c 1.0 246 10.45 .04 7 0.35 174 12.45 .05

A Hcxammine cobalt (Ill) chloride B Tris(ethylenediamir1e) cobalt (Ill) chloride C Hexttmminc cobalt (Ill) acetate Curve compression measures the photographic speed differences at a density of 1.0 when processing the element in the Roller Transport Processor at speeds of 2.3 feet per minute and 4.l feet per minute.

EXAMPLE I CONTROL A fine grain silver chlorobromoiodide gelatin emulsion containing 90 mole percent chloride, 9 mole percent bromide and 1 mole percent iodide is chemically sensitized with sulfur and gold sensitizers. To the emulsion is added 200 mg. of oleic ether of polyethyleneglycol (m.w. l540)/silver mole. Sixty-nine grams per mole of silver of a synthetic polymer vehicle is also added to the emulsion. The vehicle added is 32/3/65 (mole percentages) methyl acrylate/3- acryloyloxypropane-l-sulfonic acid, sodium salt/2- acetoacetoxyethyl methacrylate. The emulsion is then coated on a polyethylene terephthalate support at a coverage of 50.5 mg. of silver per square decimeter and 50.5 mg. of gelatin per square decimeter. A normal gelatin overcoat of 9.2 of gelatin per square decimeter is coated over the emulsion layer. The coated element is then exposed, using tungsten illumination, to a step wedge through a neutral halftone screen. The element Dot quality if a measure of the quality of the reproduction of a halftone image. Lithtype photographic elements exposed to a halftone image, and developed, produce areas commonly referred to as shadow dots and areas known as highlight areas. Intermediate between these two extremes are areas of varying size. The dot qualtiy used herein is a measure of the areas referred to as 50 percent dots (i.e., one-half clear and one-half developed density) and is expressed in a progressive scale where 9 is excellent and l is extremely poor. A 50 percent dot quality below 6 is generally not acceptable.

EXAMPLE 5 This example illustrates that all cobalt compounds do not impart desirable photographic properties. Elements are prepared and processed in a manner similar to that of Example 1 except that the following compounds are added:

Cobaltous (ll) chloride D EXAMPLE 9 Potassium hexacyanocobaltate (lll) E q 1 i F Example I is repeated except that 0.5 gram of 5- T"m"odiethylenemamme cobalt G bromo-S-hydroxy-6-methyl-l ,3,3a, 7-tetrazaindene per Th I h T b] n 5 mole of silver and 1.0 gram of hexammine cobalt (Ill) e resu ts are 8 Own m a e chloride per mole of silver are added to the emulsion A L ll prior to coating. The results are shown in Table lll.

l0 Feature Relative EXAMPLE g/"mle speed Gamma Quahty 10 Example 9 is repeated except that tris(ethylenedia- D 78 low .04 5 mine) cobalt (lll) chloride is substituted on an equal D .25 74 11.75 .04 6 weight basis for the hexammine cobalt (lll) chloride D 63 6 lo therein. The results are shown in Table [I]. E .1 91 12.35 .04 5 amp yed E .5 6O ll.82 .04 s F 1.0 severe 0.22 .04 0 EXAMPLE ll desensitization I 5 F29 f ggz 0 Example 9 is repeated except that 5,7-dihydroxy- G 1.0 41 3.62 .04 6 l,2,3,4, G-pentazaindene is substituted on an equal G Y Q05 94 9 weight basis for the tetrazaindene employed therein.

desensmzation The results are shown in Table III.

TABLE Ill Fresh Curve Incubation Ex- Feature Rel. Dot Compre- Rel. ample g/mole Ag. Speed Gamma Fog Quality ssion Speed Gamma Fog 6 A (1.0) 589 12.2 .04 7 0.42 log E 832 12.22 .04

B (0.5) 7 A (1.0) 676 12.3 .04 7 0.38 log E 795 11.75 .04

B (1.0) 8 A (1.0) 676 ll.85 .04 7 0.24 log E 355 12.30 .08

C (1.0) 9 D( .5) 832 11.87 .04 7 0.27logE 617 12.50 .12

B (1.0) 10 D( .5) I180 11.07 .04 7 0.31 log E 708 12.47 .24

C (1.0) 11 C (1.0) 680 11.98 .04 8 0.10 log E 560 11.55 .04

A 4-Hydroxy-6-mcthyl-LSJaJ-tctrauindenc B Hexammine cobalt (lll) chloride C Tris(ethylcnediarninc) cobalt (lll) chloride D S-Bromo-S-hydroxy-b-mcthyll ,3.3a,7-tetrmindcne E 5.7-dihydroxy-l .2.3,4,6-pentauindenc Although the theory of this invention is not clearly EXAMPLE l2 understood, it is believed that the difference between those complexes which are operable and those which are not lies in their stability constants, those complexes having higher stability constants being operable.

When tested in a similar manner, zinc and nickel complexes are found to yield no positive results.

EXAMPLE 6 Example 1 is repeated except 1.0 gram per mole of silver of 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene and 0.5 gram per mole of silver of hexammine cobalt (lll) chloride are added to the emulsion prior to coating. The results are shown in Table III.

EXAMPLE 7 Example 6 is repeated except that the concentration of hexammine cobalt (lll) chloride is increased to l gram per mole of silver. The results are shown in Table Ill.

EXAMPLE 8 Example 7 is repeated except that tris(ethylenediamine) cobalt (lll) chloride is substituted on an equal weight basis for the hexammine cobalt (lll) chloride employed therein. The results are shown in Table III.

EXAMPLE 13 Example 2 is repeated except that bis(diethanolamine) cobalt (lll) chloride is substituted on an equal weight basis for the hexammine cobalt (lll) chloride employed therein. The results are somewhat poorer than those obtained in Example 2. but better than the results obtained in Example 1.

EXAMPLE 14 Example 14 is repeated except that bis(dipropanolamine) cobalt (lll) chloride is substituted on an equal weight basis for the bis(diethanolamine) cobalt (lll) chloride employed therein. Results equivalent to those of Example l3 are obtained.

EXAMPLE Example 2 is repeated except that tris(trimethylenediamine) cobalt (III) chloride is substituted on an equal weight basis for the hexammine cobalt (III) chloride employed therein. The results are shown in Table IV.

EXAMPLE 16 Example 2 is repeated except that ethylenediaminebis (trimethylenediamine) cobalt (III) chloride is substituted on an equal weight basis for the hexammine cobalt (III) chloride employed therein. The results are shown in Table IV.

EXAMPLE 17 Example 2 is repeated except that Bis(ethylenediamine) trimethylenediamine cobalt (III) chloride is substituted on an equal basis for the hexammine cobalt (III) chloride employed therein. The results are shown in Table IV.

EXAMPLE l8 Example 2 is repeated except that tris(ethylenediamine) chromium (III) chloride is substituted on an equal weight basis for the hexammine cobalt (III) chloride therein. The results are shown in Table IV.

The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

What is claimed is:

l. A photographic element comprising a support having coated thereon at least one layer comprising a photographic silver halide emulsion and in said layer or in a second layer adjacent thereto from about 0.2 to about 5.0 grams per mole of silver of each of (a) at least one azaindene and (b) at least one hexacoordinated trivalent cationic complex comprising a trivalent metal ion selected from the group consisting of cobalt (III) and chromium (III) in combination with at least one ligand selected from the group consisting of ammonia, ethylenediamine, trimethylenediamine, diethanolamine and dipropanolamine; said silver halide emulsion comprising silver halide grains in which the halide consists of at least about 50 mole percent chloride, up to about 10 mole percent iodide and any remaining halide being bromide.

2. The element of claim 1 wherein the hexacoordinated trivalent cationic complex is present in the silver halide emulsion layer.

3. The element of claim I wherein the trivalent metal ion is cobalt (III).

4. The element of claim 1 wherein the trivalent metal ion is chromium (Ill).

5. The element of claim 1 wherein the support is a poly(ethylene terephthalate) film.

6. The element of claim 1 comprising at least one layer containing an alkylcne oxide polymer.

7. The element of claim 1 further comprising at least one synthetic polymer vehicle.

8. A photographic element comprising a support having coated thereon at least one layer comprising a photographic silver halide emulsion and in said layer or in a second layer adjacent thereto from about 0.2 to about 5.0 grams per mole of silver of each of (a) at least one azaindene and (b) at least one hexacoordinated trivalent cationic complex selected from the group consist' ing of hexammine cobalt (Ill) and tris (ethylenediamine) cobalt (III); said silver halide emulsion comprising silver halide grains in which the halide consists of at least about 50 mole percent chloride, up to about l0 mole percent iodide and any remaining halide being bromide.

9. The element of claim 8 wherein the hexacoordinated trivalent cationic complex is present in the silver halide emulsion layer.

10. The element of claim 8 comprising at least one layer containing an alkylene oxide polymer.

ll. The element of claim 8 further comprising at least one synthetic polymer vehicle.

12. A high contrast photographic element comprising a poly(ethylene terephthalate) film support having coated thereon at least one layer comprising a photographic silver halide emulsion, from about 0.3 to about 3.0 grams per mole of silver of at least one hexacoordinated trivalent cationic complex selected from the group consisting of hexammine cobalt (III) and tris (ethylenedimaine) cobalt (Ill), and from about 0.2 to about 5.0 grams per mole of silver of at least one azaindene; said silver halide emulsion comprising silver halide grains in which the halide consists of at least about 50 mole percent chloride, up to about 10 mole percent iodide and any remaining halide being bromide.

13. The element of claim 12 wherein the azaindene is selected from the group consisting of 4-hydroxy-6- methyl-1,3,3a, 7-tetrazaindene and 5-bromo-5- hydroxy-6-methyl-l ,3,3a, 7-tetrazaindene.

14. The element of claim 12 comprising at least one layer containing an alkylene oxide polymer.

15. The element of claim 12 further comprising at least one synthetic polymer vehicle. 

1. A PHOTOGRAPHIC ELEMENT COMPRISING A SUPPORT HAVING COATED THEREON AT LEAST ONE LAYER COMPRISING A PHOTOGRAPHIC SILVER HALIDE EMULSION AND IN SAID LAYER OR IN A SECOND LAYER ADJACENT THERETO FROM ABOUT 0.2 TO ABOUT 5.0 GRAMS PER MOLE OF SILVER OF EACH OF (A) AT LEAST ONE AZAINDENE AND (B) AT LEAST ONE HEXACOORDINATED TRIVALENT CATIONIC COMPLEX COMPRISING A TRIVALENT METAL ION SELECTED FROM THE GROUP CONSISTING OF COBALT (III) AND CHROMIUM (III) IN COMBINATION WITH AT LEAST ONE LIGAND SELECTED FROM THE GROUP CONSISTING OF AMMONIA, ETHYLENEDIAMINE, TRIMETHYLENEDIAMINE, DIETHANOLAMINE AND DIPROPANOLAMINE; SAID SILVER HALIDE EMULSION COMPRISING SILVER HALIDE GRAINS IN WHICH THE HALIDE CONSISTS OF AT LEAST ABOUT 50 MOLE PERCENT CHLORIDE, UP TO ABOUT 10 MOLE PERCENT IODIDE AND ANY REMAINING HALIDE BEING BROMIDE.
 2. The element of claim 1 wherein the hexacoordinated trivalent cationic complex is present in the silver halide emulsion layer.
 3. The element of claim 1 wherein the trivalent metal ion is cobalt (III).
 4. The element of claim 1 wherein the trivalent metal ion is chromium (III).
 5. The element of claim 1 wherein the support is a poly(ethylene terephthalate) film.
 6. The element of claim 1 comprising at least one layer containing an alkylene oxide polymer.
 7. The element of claim 1 further comprising at least one synthetic polymer vehicle.
 8. A photographic element comprising a support having coated thereon at least one layer comprising a photographic silver halide emulsion and in said layer or in a second layer adjacent thereto from about 0.2 to about 5.0 grams per mole of silver of each of (a) at least one azaindene and (b) at least one hexacoordinated trivalent cationic complex selected from the group consisting of hexammine cobalt (III) and tris (ethylenediamine) cobalt (III); said silver halide emulsion comprising silver halide grains in which the halide consists of at least about 50 mole percent chloride, up to about 10 mole percent iodide and any remaining halide being bromide.
 9. The element of claim 8 wherein the hexacoordinated trivalent cationic complex is present in the silver halide emulsion layer.
 10. The element of claim 8 comprising at least one layer containing an alkylene oxide polymer.
 11. The element of claim 8 further comprising at least one synthetic polymer vehicle.
 12. A high contrast photographic element comprising a poly(ethylene terephthalate) film support having coated thereon at least one layer comprising a photographic silver halide emulsion, from about 0.3 to about 3.0 grams per mole of silver of at least one hexacoordinated trivalent cationic complex selected from the group consisting of hexammine cobalt (III) and tris (ethylenedimaine) cobalt (III), and from about 0.2 to about 5.0 grams per mole of silver of at least one azaindene; said silver halide emulsion comprising silver halide grains in which the halide consists of at least about 50 mole percent chloride, up to about 10 mole percent iodide and any remaining halide being bromide.
 13. The element of claim 12 wherein the azaindene is selected from the group consisting of 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene and 5-bromo-5-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene.
 14. The element of claim 12 comprising at least one layer containing an alkylene oxide polymer.
 15. The element of claim 12 further comprising at least one synthetic polymer vehicle. 